Title : The influence of water temperature changes on the spawning period of the Baltic sprat (Sprattus sprattus balticus)
Abstract:
The Baltic sprat (Sprattus sprattus balticus) is a small pelagic fish and one of the key commercial species in the Baltic Sea, with annual landings exceeding those of other ichthyofaunal taxa in the region. As an important component of the marine food web, sprat plays a crucial role in ecosystem functioning as a prey species for predator fishes. Advancing knowledge of its biology and ecology provides essential input for the sustainable management of marine living resources and fisheries in the Baltic Sea.
A long-term dataset spanning more than 50 years (from 1970 onwards) indicates a shift toward an earlier onset of sprat spawning in the southern Baltic. Over the same period, an increase in water temperature has been observed, reflecting ongoing climate-driven changes in the marine environment. Such changes may significantly influence reproductive processes, including the timing, duration, and intensity of spawning.
The present study aims to assess long-term variability in the timing and duration of Baltic sprat spawning and to evaluate the extent to which these changes are associated with water temperature. To determine the duration of spawning, information on the gonad development stage collected during ichthyological analysis was used. Thus, allowing for a detailed examination of reproductive phenology over multiple decades. The results provide insight into temporal trends in sprat reproduction and their potential links to environmental drivers.
This research contributes to a better understanding of climate-related changes in sprat spawning phenology and can support further studies as well as ecosystem-based fisheries management in the Baltic Sea.
